Copernican (R)evolution?

Copernican Cosmology

Copernicus and the Scientific Revolution

In 1962 Thomas Kuhn first published his seminal study on Copernicus, The Structure of Scientific Revolutions. This book has become influential in trying to explain the development of modern science and set the stage for the discussion of a “scientific revolution.” While previous work spoke of a “scientific revolution,” Kuhn tried to identify the factors that structured this revolution. But should we fully accept Kuhn’s analysis?

Kuhn’s Analysis

Kuhn argued that the Copernican system became a catalyst for greater scientific investigation and empiricism. This change was not because the Copernican system was inherently superior to the Ptolemaic system. Rather it had numerous problems itself. To illustrate, look at the above image, which comes from an edition of the Harmonia Macrocosmica. While the sun is the center of the solar system, the Copernican solar system retained the perfection of the spheres, or in other words that paths of the heavenly bodies were in perfect circles, much like the Ptolemaic system. As a result, many of the same problems persisted, such as trying to problems of calculating Mars movement.

Nevertheless, Kuhn tried to demonstrate that what marked the Copernican system was its simplicity, a quality that provided a more efficient model for others to probe and perfect. Due to this concision, astronomers started to investigate the evidence more precisely, ultimately leading to the great astronomical communities and the beginnings of the early modern science. Compared to the Ptolemaic model, Copernicus certainly did simplify. By the 16th century, the Ptolemaic model had adapted and morphed into a complicated system of concentric circles.

Aristotelian-Ptolemaic sphere. The earth sits in the center surrounded by numerous spheres that held celestial objects in perfect orbits around the earth. However, in order to account for retrograde motion, additional circles were added to the system that are visible through the cross-aligned sections.

Models, like the one pictured above, are a poignant illustration of how complicated the system had became. In addition to the spheres with fixed objects, the system developed internal concentric circles. These circles were the paths of planetary motion which were developed in order to explain retrograde motion. Contrary to popular belief, this system was sufficiently accurate to account for most motion, despite its inaccuracy. However, with Copernicus’ publication, he developed a system that was able to account for much of the retrograde motion and eliminate the cumbersome internal “epicycles,” the name given to the rotations in each sphere. Because the theory directly challenged accepted authority, and since it required more observations to address the issues it raised, the system led to a new kind of observational based science. In Kuhn’s perspective, this developed a new paradigm, a shift in the epistemelogical structures. An event that was not just a process over time but in fact an immediate event, a revolution.

Models of Evolution

Although Kuhn offered a new model on science and its progress as a rupture or revolution from the past, this thesis has directly come under attack, and brings into question whether there was a scientific revolution at all. What if Copernicus was not so inventive? This is the point raised by George Saliba, who has written extensively on how Arabic science played a formative role in Copernicus’ theories (Rethinking the Roots of Modern Science, 1999; Islamic Science and the Making of the European Renaissance, 2007). Saliba generally tries to unsettle Western accounts on the development of modern science by moving his focus East. As a mathematician himself, he addresses the mathematical tradition during the Golden Age of Arabic learning. Numerous Arabic mathematicians already noticed the problems with the Aristotelian-Ptolemaic model of the universe. They had equally provided solutions. One simple example is Al-Farabi. Seeking to create a holistic philosophy, Al-Farabi recalculated the circumference of the earth as a part of his synthesis of Aristotle’s geography (For more information on Al-Farabi, see Dimitri Gutas, Al Farabi).  For those who are rethinking modern science, they are trying to emphasize the longue durée, the process of production rather than the event. This historical perspective sees modern science as being tied to a longer process of events that occurred through interaction, borrowing, trial, error, and more. It is just as sociological, yet highlights similarity over difference.

The diagram of the Copernican system adjusts cosmologies. While Copernicus rejected the heliocentric model, he still believed that God must have created the heavens in perfection, and therefore assumed that circles must remain as the model of motion.


So is it a Copernican Revolution or Copernican Evolution? Naturally this question falls within a wider question of historiography. For the economic or structuralist historian the question largely falls into an event. While numerous factors contribute to the production and change, those very factors work to tip the scales, once out-balanced they dramatically fall and produce rapid, epistemic changes (For more examples in this tradition, see Christopher Beckwith, Warriors of the Cloisters, 2012; Kenneth Pomeranz, The Great Divergence, 2000). On the other hand, cultural historians and those in post-colonial studies emphasize the inherent Euro-centrism of such structuralist models. They bring to light the cultural interactions and connectivity of events, deconstructing causation and emphasizing the notion of evolution and collaboration, whether virtuous or vicious (For an example of this kind of interpretation, check Arun Batla, The Dialogue of Civilizations in the Birth of Modern Science, 2006). How should we discuss this issue then? Well, it comes down to how we practice history.

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